Convertible hospital bed-chair



March 15, 1966 B. R. F. M DONALD 3,239,853

CONVERTIBLE HOSPITAL BED-CHAIR Filed Jan. 15, 1962 2 SheetsSheet 1 Fig.3. I Z

United States Patent 3,239,853 CONVERTEBLE HOSPITAL BED-CHAIR Benjamin R. F. MacDonald, 27 40 Telegraph Ave, Berkeley, Calif. Filed Jan. 15, 1962, Ser. No. 166,241 6 Claims. (Cl. 68)

This application is a continuation-in-part of my prior copending application S.N. 820,678, now abandoned.

The present invention relates generally to hospital beds, and more particularly to a hospital bed having an adjustably foldable mattress spring frame which is also pivotal between positions parallel and transverse to the bed and convertible to a chair in the transverse position.

Various hospital beds are known wherein the mattress spring frame is formed in several independently vertically foldable sections. Such beds enable a patient to be moved from a flat reclining position in the bed to a variety of advantageous positions, e.g., a partially sitting position. Suitable mechanical adjusting means are conventionally coupled to the foldable sections to enable the various positions to be assumed with no exertion to the patient and with a minimum of effort to a nurse or other attendant.

Although foldable beds of the foregoing type have done much to further patient comfort and facilitate more efficient nursing operations, patients are still subjected to discomfort and valuable nursing hours are lost in moving patients from their beds to chairs wherein they can assume a more comfortable sitting position, desirable in many cases at various times during the day. Advantages are therefore to be gained by the provision of a foldable mattress spring frame in a hospital bed wherein the conventional adjustment mechanism is retained and in addition the frame is selectively pivoted from the usual position parallel to the bed to a position transversely thereof. With the added capability of the frame being pivotal, the frame may be readily adapted to a chair-like configuration for employment in the transverse position. The patient may then be gently and easily placed in a normal full sitting position without necessitating his. removal from the bed. Moreover, such transverse chair position enables a patient to get off of or onto the bed with a minimum of effort, and also, and of extreme importance, the bed may thus be positioned to facilitate ready and proper use of a bed pan by the patient while remaining on the bed.

Formidable problems are encountered, however, in providing in a hospital bed an adjustably foldable mattress spring frame which is also pivotal and which may be readily adjusted to a chair-like position. More particularly, the usual adjusting mechanism necessarily occupies a substantial portion of the underside of the spring frame such that the frame is extremely difficult to pivotally mount upon the bed frame without detracting from the full foldable adjustment capabilities of same. Further difficulties arise in the provision of arm rest forming structure and the like for facilitating ready conversion of the frame into a complete chair, which structure must be necessarily adapted for disposal in an unobstructing position upon the frame when the same is employed as a bed.

The foregoing problems and difficulties are overcome by the present invention which provides a fully adjustable foldable mattress spring frame structure which is also pivotal and readily convertible to a complete chair. The invention provides such pivotal frame structure as an integral unit of a hospital bed.

It is therefore an object of the present invention to provide a foldable mattress spring frame which is pivotal to a position transversely of a hospital bed wherein the frame may be manipulated to form a chair.

3,239,853 Patented Mar. 15, 1966 Another object of the invention is the provision of apparatus of the class described above whereby the need for separate costly and hospital space consuming special chairs is eliminated.

It is still another object of the present invention to provide a hospital bed-chair whereby a bed patient may be manipulated from a reclined position in bed to a complete sitting position in a chair without exertion to the patient and with a minimum of efiort to a nursing attendant.

A further object of this invention is the provision of a fully adjustable foldable gatch spring frame in a hospital bed, the gatch frame being capable of being swung to a transverse position and made to assume a chair configuration to enable an occupant to readily step either off or onto the bed.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of the preferred form of the invention which is illustrated in the drawings accompanying and forming part of the specification. It is to be understood, however, that variations in the showing made by the said drawings and description may be adopted within the scope of the invention as set forth in the claims.

FIGURE 1 is a side elevation view of a convertible hospital bed-chair in accordance with the present invention in extended horizontal position.

FIGURE 2 is a top plan view of the embodiment of FIGURE 1.

FIGURE 3 is a longitudinal sectional view taken at plane 33 of FIGURE 2 but showing the foldable spring frame of the bed-chair of FIGURE 1 in alternative position as a bed.

FIGURE 4 is a transverse sectional view taken at plane 44 of FIGURE 2 but showing the spring frame in chair position.

FIGURE 5 is an enlarged elevational view of a portion of the bed and illustrating particularly the means by which the head and central portions thereof may be locked in selected positions.

FIGURE 6 is a sectional view taken on the line 66 of FIGURE 5.

Considering now the invention in some detail and referring to the illustrated forms thereof in the drawings, a convertible hospital bed-chair 11 is seen to be provided by means of a remotely adjustably foldable mattress spring frame 12 which is adapted for rotation from a bed position parallel to the bed (see FIGURE 1) to a chair position at right angles thereto (see FIGURE 4).

As regards more particularly the spring frame 12 as integrally employed in a convertible bed-chair, and referring to the drawings, it is to be noted that such spring frame is supported upon a bedstead frame 13 of generally conventional construction, consisting of a head frame 14, foot frame 16, and side frames 17, 18 secured together to form a rigid structure. The spring frame 12 is formed of a plurality of foldable sections 19, 21, 22 which are normally arranged in end to end relation when occupying their position upon the bedstead. More specifically, the head section 19 and central section 21 are respectively hingedly connected at longitudinally spaced positions of a pair of transversely spaced vertical support plates 23, 24, rigidly interconnected at their bottom edges by a base plate 26. In addition a fixed horizontal spring section 27 is attached to the plates 23, 24 at the top edges thereof in interposed complementary relation between the foldable head and central sections 19, 21. The foot section 22 of the spring frame is in turn hingedly connected to the end of the central section 21. An upright transverse foot plate 28 is additionally rigidly secured across the end of foot section 22 and several upright side plates 29 are preferably secured in longitudinally space relation along both sides of the spring frame 12 in order to facilitate lashing or the like of a mattress 31 (see FIGURE 3) to the upperside of the spring frame 12 in substantially nonslipping relation thereto.

The spring frame 12 in the respects just described is substantially similar to spring frames of the gatch spring variety as employed on most conventional hospital beds. The separate foldable sections are usually remotely adjustable with the adjusting mechanism being disposed at the underside of the spring frame. In accordance with the present invention, however, the spring frame 12 is pivotally mounted upon the bedstead frame 13 and in order for the spring frame to be unobstructedly rotatable, a unique arrangement of the adjusting mechanism is required. The spring frame is mounted for rotation transversely of the bedstead frame 13 preferably by means of a vertical shaft 32 rigidly secured as by flanged attachment to the center of base plate 26. The shaft 32 is journalled within a bearing well 33 depending from a cross member 34 secured between side frames 17, 13 of the bedstead. In the event power driven rather than manual rotation of the spring frame 12 is desired, an electric motor 35 coupled to shaft 32 through a gear box 36 (see FIGURE 4) may be alternatively employed. In addition suitable longitudinal and transverse stop means such as detents (not shown) are preferably employed between plates 26, 34 to lock the spring frame at such positions of rotation.

Considering now means for remotely adjusting the folclable spring frame 12 while permitting rotation of same to a transverse position for conversion to a chair, the adjustment mechanism facilitates independent remote raising and lowering adjustment of the head and central sections 19, 21 respectively, and direct adjustment of the foot section 22 to a plurality of locked positions of rotation relative to the central section. By appropriately adjusting the individual sections, the spring frame may be manipulated into a variety of desirable bed positions, e.g., Trendelenburg, reverse Trendelenburg, hyperextension, semi-chair and other positions. In addition, the spring frame may be appropriately manipulated such that the head section 19 forms the back, the central section 21 the seat, the foot section the leg support, and the plate 23 the foot rest of a chair in the rotated transverse chair position of the spring frame.

The adjusting mechanism for the head section 19 preferably includes a pair of cog wheels 37, 38 journalled to the inner sides of vertical support plates 23, 24 and having links 39 and 41 respectively projecting radially outward therefrom. The ends of the links 39 and 41 are in turn provided with rollers which engage undersurfaces of the frame of the head section to support it in the various positions of such frame. The cog wheels 37, 38 are respectively engaged by gears 42, 43 rigidly attached to a common shaft 44 rotatably secured between support plates 23, 24 and extending transversely through one thereof for rigid end connection of an external hand crank 45. The crank may accordingly be rotated manually to effect a corresponding rotation of the links 39 and 41. Since the rollers 40 carried by the links 39 and 41 engage the frame, such rotation causes the head section to be selectively raised and lowered. By virtue of the rollers engaging the frame, substantially frictionless movement between the frame and links is provided and thus ready and easy adjustment of the head section may be attained. The adjusting mechanism for the central section 21 is similarly preferably provided as a pair of links 46 and 47 projecting radially outward from cog wheels 48 and 49 journalled to the support plates 23, 24. Rollers 55 are carried on the free ends of the links 46 and 47 to engage the central section in a manner similar to engagement of rollers 40 with the head section 19. A shaft 50 having gears 51, 52 rigidly attached thereto and engaging cog wheels 48, 49 is similarly provided such that upon Cir 4. manual operation of a hand crank 53 attached thereto, raising or lowering of the central section 21 to substantially any desired stationary position of inclination relative to fixed spring section 27 is effected.

Means are preferably provided to facilitate locking of the head and central sections 19 and 21 in any of the various positions to which they may be adjusted. A variety of locking means may be employed for this purpose, for example, the means depicted in FIGURES 5 and 6. As shown therein one of the support plates 23, 24 is provided with circular arrays of circumferentially spaced depressions 201, 202, respectively concentrically disposed about the rotational axes of the hand cranks 45, 53. Spring loaded latch bolts 203, 204 are respectively slidably disposed in bores 206, 207 through the cranks at radial positions registerable with the depressions 201, 202. The loading springs 208, 209 of the bolts normally urge them inwardly towards the plate 23 and into engagement with whatever ones of the depressions 201, 202 is aligned therewith. In order that the latch bolts may be selectively retracted to positions out of engagement with the depressions, the bolts are respectively provided with radially projecting pins 211, 212 at their outer ends. These pins are selectively engageable with the portion sof the cranks bordering the bores 206, 207 or slidable within longitudinal keyways 213, 214 communicating with the bores. It will thus be appreciated that the bolts 203, 204 may be pulled outwardly against the loading of springs 208, 209 and rotated to engage the pins 211, 212 with the exterior surfaces of the cranks as best shown in FIGURE 6. The bolts are thus retained in retracted positions whereby the cranks may be freely rotated to adjust the head and central sections 19, 21. When the desired positions of the head and central sections are approached, the latch bolts 203, 204 are rotated to align the pins with the keyways. The bolts are now free to be urged by the springs 208, 209 inwardly towards the plate 23 and into engagement with the nearest ones of the depressions 201, 202. The cranks are thus locked in position as are therefore the head and central sections of the spring frame.

In order to lock the foot section 22 in various positions of inclination relative to the central section 21 when the spring frame is in the bed position, a pair of foldable parallel spaced support arms 54, 56 are secured at one of their ends to a shaft 57 which is journalled transversely between the sides of the foot section in the end region thereof. The other ends of the arms 54, 56 are rigidly secured by a connecting arm 58 for selectively engaging longitudinally spaced teeth 59 of a pair of parallel rack members 61, 62 mounted longitudinally of the bedstead frame 13. The rack members 61, 62 may be, for example, rigidly attached between the foot frame 16 and a cross member 63 connecting the side frames 17, 18 at a longitudinal position in the region of the juncture of the foot section 22 with the central section 21. The foot section 22 may hence be directly manually rotated to various positions of inclination relative to the central section 21 and supported therein by engaging the connecting arm 58 of the support arms 54, 56 in the corresponding teeth 59 of the rack members 61, 62. The support arms 54, 56, moreover, may be pivoted to an out-of-the-way position parallel to the foot section 22 of the spring frame to facilitate unobstructed rotation of same to the transverse chair position. Suitable releasable latching means are provided to retain the arms 54, 56 in the out-of-the-way position, preferably a spring loaded latch bolt 64 secured to the underside of foot section 22 for engaging a laterally projecting rod 66 secured to one of the arms 54.

In order that the foot section 22 may be locked in a position parallel to central section 21 commensurate with unobstructed rotation of spring frame 12, the foot section is best provided with longitudinally projecting fingers 67 on opposite sides of the end thereof for engaging spring loaded latch bolts 68 secured to opposite sides of the central section when such sections are positioned parallel. The spring frame 12 may thus be prepared for rotation by locking the foot section 22 parallel to the central section 21 with the latch bolts 68 and the support arms 54, 56 parallel to the foot section with latch bolt 64. Subsequent to rotation of the spring frame to the transverse chair position, the latch bolts 68 may be retracted to thus release the foot section 22 and permit same to rotate relative to central section 21 into a chair leg rest position slightly inclined to the vertical as depicted in FIGURE 4. It will be appreciated that free rotation of the foot section under the influence of gravity might be detrimental to a bed patient occupying the bed-chair at the same time it is converted to the chair configuration. Accordingly the present invention provides a pair of dash pots 69, or equivalent motion damping means, pivotally connected between the foot and central sections at the opposite sides thereof.

The bed-chair in accordance with the present invention may additionally be provided with foldable arm members 71, 72 to facilitate conversion to a complete chair. The arm members are preferably provided as channels respectively pivotally connected at one end to the exterior sides of the head section 19 at a medial longitudinal location thereof. Elongated plate support members 73, 74 are respectively pivotally connected at the opposite ends of channel arm members 71, 72 intermediate the depending parallel sides thereof so as to be foldable into the channel space formed therebetween. The support members 73, 74 are transversely slotted at the unpivoted ends thereof as shown generally at 76 and are of a length to rigidly support the arm members 71, 72 in horizontal position when the slots 76 engage laterally projecting pins 77 of the central section 21. The slots may be disengaged from the pins and the support members 73, 74 pivoted to positions enclosed by the channeled arm members 71, 72 (see FIGURE 3) while such latter members are pivoted to an out-of-the-way rest position when the bed-chair is employed in the bed position.

The hospital bed-chair of the present invention physically described hereinbefore may hence be employed as a normal hospital bed with the sections 19, 21, 22 of the spring frame in parallel end to end relation longitudinally of bedstead frame 13 as depicted in FIGURE 1. The head and central sections 19, 21 respectively may be independently manipulated by operation of remote adjusting hand cranks 45, 53 and locked in desired positions by means of the associated latch bolts 203, 204. The latch bolts 64, 68 may in addition he opened to permit independent direct manipulation of foot section 22 and locking of same in various positions by engagement of the support arm connecting arm 58 in the teeth 59 of rack members 61, 62. By virtue of such independent manipulation of the foldable sections 19, 21, 22, the spring frame is readily transformable into a variety of bed configurations.

Conversion of the bed-chair from the bed to the chair configuration may be readily accomplished even with an occupant in the bed, the occupant being thereby manipulated into a full sitting position in the chair with no exertion on his part and a mini-mum of effort on the part of an attendant. More particularly, the central section 21 may be adjusted parallel to the fixed section 27 by operating crank 53 and the head section 19 raised toa partial chair position upwardly inclined relative to the fixed section 27 by operating crank 45, these sections being locked in position upon manipulation of the latch bolts 203, 204. As a result of the gradual raising of the head section, the bed occupant is gently urged into a partial sitting position. The foot section 22 is additionally locked parallel to the central section 21 by means of latch bolts 68 and the support arms 54, 56 are retained in unobstructing position parallel to the foot section by means of latch bolt 64. The arms 71, 72 are then rotated into horizontal position and locked therein by engaging the slots 76 of support members 73, 74 with the pins 77. The spring frame 12 with the occupant in partial sitting position is rotated to the chair position transversely of the bedstead frame 13. In this transverse position, the foot section 22 is released by opening latch bolts 68 and rotates slowly downward by virtue of dash pots 69, to a slightly inclined substantially vertical leg supporting position with the foot plate 28 forming a foot rest. A complete chair configuration is thus provided in the foregoing manner by the spring frame 12 and simultaneously the bed occupant is placed in complete sitting position therein. The back and seat of the chair (viz. head and central sections 19, 21 of the spring frame), moreover, are readily adjustable to various comfort promoting positions by manipulation of hand cranks 45, 53 and lockable in these positions by means of the latch bolts 203, 204.

What is claimed is:

1. Mattress spring frame structure for a hospital bed and convertible to a chair comprising a pivotal support base secured to a bedstead frame with the base being rotatable about an axis normal to the frame, a spring frame head section pivotally connected to one end of said base, a spring frame central section pivotally connected at one end to the other end of said base, a spring frame foot section pivotally connected to the other end of said central section, releasable latch means carried by said central section for selectively locking said foot section in parallel relation thereto, a first pair of cog wheels respectively journalled at the opposite sides of said base and having radially projecting link arm-s slidably engaging opposite sides of said head section in supporting relation thereto, a first pair of gears respectively engaging said first pair of cog wheels and journalled upon said base for selective rotation to responsively effect rotation of the head section, means for selectively locking said head section at positions throughout its rotation, a second pair of cog wheels respectively journalled at the opposite sides of said base and having radially projecting link arms slidably engaging opposite sides of said central section in supporting relation thereto, a second pair of gears respectively engaging said second pair of cog wheels and journalled upon said base for selective rotation to responsively effect rotation of the central section, means for selectively locking said central section at positions throughout its rotation, a transverse rod member pivotally secured to said foot section, a pair of transversely spaced rack members mounted longitudinally of said bedstead frame and having longitudinally spaced teeth engageable by said rod member whereby the foot section may be rotated to selected positions and locked therein by engagement of the rod member with the corresponding teeth of the rack members, and releasable latch means carried by said foot section for selectively locking said rod member in an unob-structing position of rotation in abutment with the foot section.

2. Mattress spring frame structure according to claim 1, further defined by first and second hand cranks connected to said first and second pairs of cog wheels and disposed exteriorly adjacent one side of said base, said base having pluralities of depressions in its exterior side surface respectively concentrically disposed about the axes of said cranks, and said means for selectively locking said head section and said means for selectively locking said central section respectively comprising spring loaded latch bolts carried by said first and second hand cranks and selectively movable between retracted positions and extended positions engageable with said depressions.

3. A convertible bed-chair comprising a bedstead frame, a cross member rigidly attached between the sides of said frame at an intermediate location thereof, a pair of upright support plates, a base plate rigidly interconnecting said support plates at the bottom edges thereof,

means carried by said cross member for mounting said base plate for rotation thereon, a fixed spring frame section secured between said support plates at the top edges thereof, a spring frame head section pivotally connected to said support plates at one end thereof in abutting relation to said fixed section, a spring frame central section pivotally connected to said support plates at the other end thereof in abutting relation to said fixed section, a spring frame foot section pivotally connected to the end of said central section and having longitudinal fingers at the sides thereof projecting toward the central section, a pair of spring loaded latch bolts secured to the opposite sides of said central section for releasably engaging said fingers when said foot section is rotated parallel to said central section, a foot plate transversely secured to the end of said foot section in right angle relation thereto, a first pair of cog wheels respectively journalled to said support plates and having radially projecting link arms slidably engaging opposite sides of said head section in supporting relation thereto, a first pair of gears respectively engaging said first pair of cog wheels, a shaft rigidly connected to said first pair of gears and journalled between said support plates with one end of the shaft extending through one of the support plates, a hand crank secured to the extending end of said shaft, a second pair of cog wheels respectively journalled to said support plates and having radially projecting link arms slidably engaging opposite sides of said central section in supporting relation thereto, a second pair of gears respectively engaging said second pair of cog wheels, a second shaft rigidly connected to said second pair of gears and journalled between said support plates with one end of the shaft extending through one of the support plates, a second hand crank secured to the extending end of said second shaft, :1 pair of transversely spaced support arms pivotally secured at one of their ends to said foot section and rigidly interconnected at their other ends by a rod, a pair of transversely spaced rack members mounted longitudinally of said bedstead frame and having longitudinally spaced teeth engageably by said rod, a laterally projecting rod secured to one of said support arms, a spring loaded latch bolt secured to the side of said foot section for releasably engaging said projecting rod when the support arms are rotated to a position parallel to the foot section, a pair of dash pots respectively secured between said foot and central sections at their opposite sides, and a pair of foldable chair arms respectively pivotally secured to opposite sides of said head section and each including support means for selective supporting attachment to said central section.

4. A convertible bed-chair as claimed by claim 3, further defined by said foldable chair arms each comprising a channel member pivotally connected at one end to said head section, and an elongated support member having one end pivotally connected to the free end of the channel member intermediate the depending sides thereof and the other end transversely slotted, and a pair of laterally projecting pins secured to opposite sides of said central section for respectively engaging the slots of said support members.

5. Mattress spring frame structure for a hospital bed and convertible to a chair comprising a pivotable support base secured to a bedstead frame with the base being rotatable about an axis normal to the frame, a spring frame head section pivotally connected to said base, a

spring frame central section pivotally connected to said base and extending generally away from said head section, a spring frame foot section pivotably connected to said central section, means for releasably locking said foot and central sections against rotation in one direction relative to one another, a pair of support arms pivotally secured adjacent opposite sides of said base and slidably engaging spaced side portions of said head section in supporting relation thereto, means for relatively pivoting said support arms to effect rotation of said head section, means for selectively locking said head section at different positions throughout its rotation, a second pair of support arms pivotally secured adjacent opposite sides of said base and slidably engaging spaced side portions of said central section, means for selectively pivoting said second support arms to effect rotation of said central section, means for selectively locking said central section at positions throughout its rotation, means for selectively locking said foot section at various positions throughout its rotation, and means for selectively positioning said last named means in unobstrueting relation to rotational movement of said pivotable base on said bed stead.

6. Mattress spring frame structure for a hospital bed and convertible to a chair comprising a pivotable support base secured to a bedstead frame with the base being rotatable about an axis normal to the frame, a spring frame head section pivotally connected to said base, a spring frame central section pivotally connected to said base and extending generally away from said head section, a spring frame foot section pivotally connected to said central section, means for rotating said head section to various positions and releasably maintaining said head section stationary in each such position thereof, means for rotating said central section to various positions and releasably maintaining said central section stationary in each such position thereof, means for locking said foot section at various positions throughout its rotation, a pair of arm rest members pivotally mounted respectively adjacent opposite sides of said head section, said arm rest members being pivotable from an inoperative unobstructing position adjacent said head section to an operative position extending angularly to said head section and spaced above said bedstead, and a pair of support members each pivotally connected to one of said arm rest members and adapted to support the latter members in their said operative position, said support members being pivotable to an inoperative position disposed closely adjacent and substantially parallel to their respective arm rest members.

References Cited by the Examiner UNITED STATES PATENTS 597,480 1/1898 Fellows 567 X 951,274 3/1910 Gronde 566 984,879 2/1911 Bartholome 569 1,581,994 4/1926 Duncan 560 1,631,888 6/1927 Pow 562 2,303,433 12/1942 Caldwell et al 568 2,664,329 12/1953 Kraska 108-l33 2,821,722 2/1958 Benson 5328 FRANK B. SHERRY, Primary Examiner. 

5. MATTRESS SPRING FRAME STRUCTURE FOR A HOSPITAL BED AND CONVERTIBLE TO A CHAIR COMPRISING A PIVOTABLE SUPPORT BASE SECURED TO A BEDSTEAD FRAME WITH THE BASE BEING ROTATABLE ABOUT AN AXIS NORMAL TO THE FRAME, A SPRING FRAME HEAD SECTION PIVOTALLY CONNECTED TO SAID BASE, A SPRING FRAME CENTRAL SECTION PIVOTALLY CONNECTED TO SAID BASE AND EXTENDING GENERALLY AWAY FROM SAID HEAD SECTION, A SPRING FRAME FOOT SECTION PIVOTALLY CONNECTED TO SAID CENTRAL SECTION, MEANS FOR RELEASABLY LOCKING SAID FOOT AND CENTRAL SECTIONS AGAINST ROTATION IN ONE DIRECTION RELATIVE TO ONE ANOTHER, A PAIR OF SUPPORT ARMS PIVOTALLY SECURED ADJACENT OPPOSITE SIDES OF SAID BASE AND SLIDABLY ENGAGING SPACED SIDE PORTIONS OF SAID HEAD SECTION IN SUPPORTING RELATION THERETO, MEANS FOR RELATIVELY PIVOTING SAID SUPPORT ARMS TO EFFECT ROTATION OF SAID HEAD SECTION, MEANS FOR SELECTIVELY LOCKING SAID HEAD SECTION AT DIFFERENT POSITIONS THROUGHOUT ITS ROTATION, A SECOND PAIR OF SUPPORT ARMS PIVOTALLY SECURED ADJACENT OPPOSITE SIDES OF SAID BASE AND SLIDABLY ENGAGING SPACED SIDE PORTION OF SAID CENTRAL SECTION, MEANS FOR SELECTIVELY PIVOTING SAID SECOND SUPPORT ARMS TO EFFECT ROTATION OF SAID CENTRAL SECTION, MEANS FOR SELECTIVELY LOCKING SAID CENTRAL SECTION AT POSITIONS THROUGHOUT ITS ROTATION, MEANS FOR SELECTIVELY LOCKING SAID FOOT SECTION AT VARIOUS POSITIONS THROUGHOUT ITS ROTATION, AND MEANS FOR SELECTIVELY POSITIONING SAID LAST NAMED MEANS IN UNOBSTRUCTING RELATION TO ROTATIONAL MOVEMENT OF SAID PIVOTABLE BASE ON SAID BED STEAD. 